The present invention relates generally to dust control apparatus and methods for controlling airborne particulate emissions generated during bulk material dumping operations. More particularly, the invention relates to a dust containment system for controlling and capturing airborne emissions from bottom dumping railroad cars when discharging dusty bulk materials, such as, for example, fly ash.
Fly ash is generated in large quantities as a waste product collected from stack gases in coal fired power plants. The fly ash is commonly transported by hopper type railroad cars from the power plant to a remote disposal site. The hopper cars are bottom dumped into a three-sided bunker having a partially open front side to permit access by a front end loader. The dumped fly ash is then loaded onto trucks for transport to a landfill disposal site. The fly ash generates tremendous amounts of billowing dust clouds when it is discharged from the hopper cars and also during handling by the front end loader. If unchecked, the fugitive dust escapes into the surrounding environment causing unacceptable air pollution levels.
In addition, the fly ash, even though transported in tarpaulin covered hopper cars, may become wetted and/or partially frozen during rail transport to the dumping site. As a result, the flow characteristics of the as received fly ash varies considerably depending upon the moisture content and ambient temperatures to which it was exposed during rail transport. It is, therefore, necessary at the dump site to employ a powered backhoe and operator stationed above the open hopper car to mechanically assist the flow out of the rail car. Additional personnel are located beneath the hopper car to open and close the gate doors which permits the particulate material to flow from the car. It is readily appreciated that the backhoe operator and hopper car gate operators are positioned in an extremely dusty area above the open car which creates a most unsatisfactory and potentially unhealthy work environment.
It is, therefore, an object of the present invention to overcome the problems of containing fugitive dust encountered in dumping fly ash and like dusty particulate materials from bottom dump railway cars. The present invention solves these problems by providing a dust containment system which contains and captures the particulate airborne pollutants generated during bottom car dumping and subsequent front end loading operations. In addition, the dust containment system of the present invention creates a continuous draft of clean air above the hopper car to provide a virtually dust free work environment for the backhoe operator.
Still further, the dust containment system of the present invention provides an enclosure and controlled air draft around the rail car and within the hopper pit to contain and capture airborne particulates within the enclosure so as to prevent its escape into the surrounding environment. This is accomplished without the need for a separate dust collector building, extensive ducting, powerful fans and like expensive equipment commonly found in prior air pollution control installations.